The Problem: On the morning of Wednesday, June 20, smack in the middle of one of the busiest travel weeks, United Airlines' primary flight operations system crashed. A United spokeswoman says an employee accidentally disabled the computers while running a routine test on Unimatic, United's flight operations system. More than 260 United flights were delayed for an average of 90 minutes, and nearly 70 other flights were canceled altogether. "It's unfortunate, but we're developing new processes that will prevent future issues like these from impacting our customers," says spokeswoman Robin Urbanski. Making matters worse, Urbanski says, was that the snafu also knocked out Unimatic's backup system.

The Lesson: Redundancy isn't the greatest thing in conversation, but for systems operations, it's a must. Backup systems must be tested and tested again to ensure they'll work when needed. And if a system goes down, locating the problem—and fixing it quickly—can be the difference between a minor delay and an all-out business shutdown. And in a high-traffic period, a major snafu can both hurt the bottom line and damage customer loyalty.